Imaging plate coating composite composed of fluoroelastomer and aminosilane crosslinkers

ABSTRACT

Provided is a polymer coating composition for a surface layer, comprising a product of a grafting reaction between a fluoroelastomer and at least one of an aminosilane component and an aminofunctionalized fluorosilicone component.

PRIORITY CLAIM

This application is a divisional application of and claims priority toU.S. patent application Ser. No. 14/229,350, filed on Mar. 28, 2014 (nowallowed) the disclosure of which is hereby incorporated herein byreference in its entirety.

DETAILED DESCRIPTION

Field of the Disclosure

The disclosure relates to fluoropolymers for printing applications. Inparticular, the disclosure relates to fluoroelastomers comprisinggrafted fluorinated polymers suitable for forming topcoat layers intransfix blankets.

Background

In aqueous ink indirect printing, an aqueous ink is jetted on to anintermediate imaging surface, which can be in the form of a blanket. Theink is partially dried on the blanket prior to transfixing the image toa media substrate, such as a sheet of paper. To ensure excellent printquality it is desirable that the ink drops jetted onto the blanketspread and become well-coalesced prior to drying. Otherwise, the inkimages appear grainy and have deletions. Lack of spreading can alsocause missing or failed inkjets in the print heads to produce streaks inthe ink image. Spreading of aqueous ink is facilitated by materialshaving a high energy surface.

However, in order to facilitate transfer of the ink image from theblanket to the media substrate after the ink is dried on theintermediate imaging surface, a blanket having a surface with arelatively low surface energy is preferred. Rather than providing thedesired spreading of ink, low surface energy materials tend to promote“beading” of individual ink drops on the image receiving surface.

Thus, an optimum blanket for an indirect image transfer process musttackle both the challenges of wet image quality, including desiredspreading and coalescing of the wet ink; and the image transfer of thedried ink. The first challenge —wet image quality—prefers a high surfaceenergy blanket that causes the aqueous ink to spread and wet thesurface. The second challenge—image transfer—prefers a low surfaceenergy blanket so that the ink, once partially dried, has minimalattraction to the blanket surface and can be transferred to the mediasubstrate.

Various approaches have been investigated to provide a solution thatbalances the above challenges. These approaches include blanket materialselection, ink design and auxiliary fluid methods. Fluoroelastomers(FKM) materials have been investigated for their use in fusersubsystems, and for potential application as blanket materials. However,there is a need to continue developing new composite materials which canbe cured at lower temperature with low extractability, are flowcoatable, and offer higher or comparable in mechanical strength.Identifying and developing new composites would be considered a welcomeadvance in the art.

SUMMARY

In an embodiment, there is a polymer coating composition for a surfacelayer, comprising a product of a grafting reaction between afluoroelastomer and at least one of an aminosilane component and anaminofunctionalized fluorosilicone component.

In another embodiment, there is a method for forming a coating. Themethod can include forming a graft polymer composition by grafting atleast one of an aminosilane component and an aminofunctionalizedfluorosilicone component with a fluoroelastomer. The method can alsoinclude crosslinking the at least one of an aminosilane component and anaminofunctionalized fluorosilicone component. The method can alsoinclude depositing a layer of the graft polymer composition on asubstrate, and curing the layer to form a grafted polymer coating.

In yet another embodiment, there is a printing system. The printingsystem can include an imaging member. The imaging member can include asubstrate and a surface layer composite disposed on the substrate. Thesurface layer composite can be formed from a composition that includes aproduct of a grafting reaction between a fluoroelastomer and at leastone of an aminosilane component and an aminofunctionalizedfluorosilicone component.

The polymer coating compositions of the present disclosure can provideone or more of the following advantages: lower curing temperature thanconventional compositions for similar applications, low extractabilityand flow coatable compositions, compositions that can be cured intolayers that have higher or comparable mechanical strength toconventionally prepared layers.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory onlyand are not restrictive of the present teachings, as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate embodiments of the presentteachings and together with the description, serve to explain theprinciples of the present teachings.

FIG. 1A depicts a cross-sectional view of an illustrative transfixblanket for a printer, according to one or more embodiments.

FIG. 1B is a schematic drawing of an aqueous indirect inkjet printerthat prints sheet media, according to an embodiment of the presentdisclosure.

FIG. 2A shows a synthesis mechanism for forming a fluoroelastomer inaccordance with an embodiment (dehydrofluorination);

FIG. 2B shows a synthesis mechanism for forming a fluoroelastomer inaccordance with an embodiment (addition of amine across the doublebond);

FIG. 2C shows a synthesis mechanism for forming a fluoroelastomer inaccordance with an embodiment (hydrolysis);

FIG. 2D shows a synthesis mechanism for forming a fluoroelastomer inaccordance with an embodiment (condensation and addition of amine acrossunsaturated fluoroelastomer);

FIGS. 3A-3B show synthesis mechanisms for forming a fluoroelastomer inaccordance with an embodiment (dehydrofluorination);

FIG. 3C-D show synthesis mechanisms for forming a fluoroelastomer inaccordance with an embodiment (addition of amine across the doublebond);

FIG. 3E-3F show synthesis mechanisms for forming a fluoroelastomer inaccordance with an embodiment (hydrolysis);

FIG. 3G shows a synthesis mechanism for forming a fluoroelastomer inaccordance with an embodiment (condensation of hydrolyzed aminosilaneagent onto an aminofunctionalized fluorosilicone-graftedfluoroelastomer);

FIG. 4A is a flowchart of a process for forming a fluoroelastomer andtopcoat in accordance with an embodiment; and

FIG. 4B is a flowchart of a process for forming a fluoroelastomer andtopcoat in accordance with an embodiment.

It should be noted that some details of the figures have been simplifiedand are drawn to facilitate understanding of the embodiments rather thanto maintain strict structural accuracy, detail, and scale.

DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to embodiments of the presentteachings, examples of which are illustrated in the accompanyingdrawings. In the drawings, like reference numerals have been usedthroughout to designate identical elements. In the followingdescription, reference is made to the accompanying drawing that forms apart thereof, and in which is shown by way of illustration a specificexemplary embodiment in which the present teachings may be practiced.The following description is, therefore, merely exemplary.

As used herein, the terms “printer,” “printing device,” or “imagingdevice” generally refer to a device that produces an image on printmedia with aqueous ink and may encompass any such apparatus, such as adigital copier, bookmaking machine, facsimile machine, multi-functionmachine, or the like, which generates printed images for any purpose.Image data generally include information in electronic form which arerendered and used to operate the inkjet ejectors to form an ink image onthe print media. These data can include text, graphics, pictures, andthe like. The operation of producing images with colorants on printmedia, for example, graphics, text, photographs, and the like, isgenerally referred to herein as printing or marking. Aqueous inkjetprinters use inks that have a high percentage of water relative to theamount of colorant and/or solvent in the ink.

The term “printhead” as used herein refers to a component in the printerthat is configured with inkjet ejectors to eject ink drops onto an imagereceiving surface. A typical printhead includes a plurality of inkjetejectors that eject ink drops of one or more ink colors onto the imagereceiving surface in response to firing signals that operate actuatorsin the inkjet ejectors. The inkjets are arranged in an array of one ormore rows and columns. In some embodiments, the inkjets are arranged instaggered diagonal rows across a face of the printhead. Various printerembodiments include one or more printheads that form ink images on animage receiving surface. Some printer embodiments include a plurality ofprintheads arranged in a print zone. An image receiving surface, such asan intermediate imaging surface, moves past the printheads in a processdirection through the print zone. The inkjets in the printheads ejectink drops in rows in a cross-process direction, which is perpendicularto the process direction across the image receiving surface.

As used in this document, the term “aqueous ink” includes liquid inks inwhich colorant is in a solution, suspension or dispersion with a liquidsolvent that includes water and/or one or more liquid solvents. Theterms “liquid solvent” or more simply “solvent” are used broadly toinclude compounds that may dissolve colorants into a solution, or thatmay be a liquid that holds particles of colorant in a suspension ordispersion without dissolving the colorant.

Described herein is a composition, for example, a composition for atopcoat layer of a blanket, comprising the product of a graftingreaction between a fluoroelastomer and at least one of an aminosilanecomponent and an aminofunctionalized fluorosilicone component. In otherwords, there is a preliminary composition that can undergo a graftingreaction to form a product composition. The product of the graftingreaction can be a fluoroelastomer-aminosilane grafted polymer composite,wherein the aminosilane component grafted on the fluoroelastomer is acrosslinker. The product of the grafting reaction can be afluoroelastomer-aminofunctionalized fluorosilicone grafted polymercomposite, wherein the aminofunctionalized fluorosilicone componentgrafted on the fluoroelastomer is a crosslinker and can be crosslinkedwith an aminosilane crosslinker. The composition can be utilized forproducing a topcoat layer of an imaging blanket for aqueous printprocesses, for a digital architecture for lithographic inks, and for afuser member as described further below.

FIG. 1A depicts a schematic cross-sectional view of an illustrativetransfix blanket 100 for a printer (e.g., an indirect aqueous inkjetprinter), according to one or more embodiments disclosed. The blanket100 may include a first or substrate layer 110. The substrate layer 110may be made from or include polyimide, aluminum, woven fabric, orcombinations thereof.

A second or conformance layer 120 may be disposed at least partially onand/or over the substrate layer 110. The conformance layer 120 may havea depth or thickness 122 ranging from about 500 μm to about 7000 μm,about 1000 μm to about 5000 μm, or about 2000 μm to about 4000 μm. Theconformance layer 120 may be made from a composite material. Moreparticularly, the conformance layer 120 may be made from or include apolymer matrix. The polymer matrix may be or include silicone, acrosslinked silane, or a combination thereof.

The conformance layer 120 may also include one or more filler materialssuch as silica, alumina, iron oxide, carbon black, or a combinationthereof. The filler materials may be present in the conformance layer120 in an amount ranging from about 0.1 wt % to about 20 wt %, about 1wt % to about 15 wt %, or about 2 wt % to about 10 wt %.

A third or tiecoat/adhesive layer 130 may be disposed at least partiallyon and/or over the conformance layer 120. The adhesive layer 130 mayhave a depth or thickness 132 ranging from about 0.05 μm to about 10 μm,about 0.25 μm to about 5 μm, or about 0.5 μm to about 2 μm. The adhesivelayer 130 may be made from a silane, an epoxy silane, an amino silaneadhesive, or a combination thereof. In another embodiment, the adhesivelayer 130 may be made from a composite material. More particularly, theadhesive layer 130 may be made from or include a polymer matrix. Thepolymer matrix may be or include silicone, a cross-linked silane, or acombination thereof.

A fourth or topcoat layer 140 may be disposed at least partially onand/or over the adhesive layer 130. The topcoat layer 140 may have adepth or thickness 142 ranging from about 500 nm to about 200 μm, about1 μm to about 150 μm, or about 5 μm to about 100 μm.

FIG. 1B depicts an illustrative printer 200 including the transfixblanket 100, according to one or more embodiments disclosed. The printer200 may be an indirect aqueous inkjet printer that forms an ink image ona surface of the blanket 100. The blanket 100 may be mounted about anintermediate rotating member 212. The ink image may be transferred fromthe blanket 100 to media passing through a nip 218 formed between theblanket 100 and a transfix roller 219.

A print cycle is now described with reference to the printer 200. A“print cycle” refers to operations of the printer 200 including, but notlimited to, preparing an imaging surface for printing, ejecting ink ontothe imaging surface, treating the ink on the imaging surface tostabilize and prepare the image for transfer to media, and transferringthe image from the imaging surface to the media.

The printer 200 may include a frame 211 that supports operatingsubsystems and components, which are described below. The printer 200may also include an intermediate transfer member, which is illustratedas a rotating imaging drum 212. The imaging drum 212 may have theblanket 100 mounted about the circumference of the drum 212. The blanket100 may move in a direction 216 as the member 212 rotates. The transfixroller 219 may rotate in the direction 217 and be loaded against thesurface of blanket 100 to form the transfix nip 218, within which inkimages formed on the surface of blanket 100 are transfixed onto a printmedium 249. In some embodiments, a heater in the drum 212 or in anotherlocation of the printer heats the blanket 100 to a temperature in arange of, for example, approximately 50° C. to approximately 70° C. Theelevated temperature promotes partial drying of the liquid carrier thatis used to deposit the hydrophilic composition and the water in theaqueous ink drops that are deposited on the blanket 100.

A surface maintenance unit (“SMU”) 292 may remove residual ink left onthe surface of the blanket 100 after the ink images are transferred tothe print medium 249. The SMU 292 may include a coating applicator, suchas a donor roller (not shown), which is partially submerged in areservoir (not shown) that holds a hydrophilic polyurethane coatingcomposition in a liquid carrier. The donor roller may rotate in responseto the movement of the blanket 100 in the process direction. The donorroller may draw the liquid polyurethane composition from the reservoirand deposit a layer of the polyurethane composition on the blanket 100.As described below, the polyurethane composition may be deposited as auniform layer having any desired thickness. After a drying process, thedried polyurethane coating may substantially cover a surface of theblanket 100 before the printer 200 ejects ink drops during a printprocess. The SMU 292 may be operatively connected to a controller 280,described in more detail below, to enable the controller 280 to operatethe donor roller, as well as a metering blade and a cleaning blade todeposit and distribute the coating material onto the surface of theblanket 100 and to remove un-transferred ink and any polyurethaneresidue from the surface of the blanket 100.

The printer 200 may also include a dryer 296 that emits heat andoptionally directs an air flow toward the polyurethane composition thatis applied to the blanket 100. The dryer 296 may facilitate theevaporation of at least a portion of the liquid carrier from thepolyurethane composition to leave a dried layer on the blanket 100before the intermediate transfer member passes one or more printheadmodules 234A-234D to receive the aqueous printed image.

The printer 200 may also include an optical sensor 294A, also known asan image-on-drum (“IOD”) sensor, which is configured to detect lightreflected from the blanket 100 and the polyurethane coating applied tothe blanket 100 as the member 212 rotates past the sensor. The opticalsensor 294A includes a linear array of individual optical detectors thatare arranged in the cross-process direction across the blanket 100. Theoptical sensor 294A generates digital image data corresponding to lightthat is reflected from the blanket 100 and the polyurethane coating. Theoptical sensor 294A generates a series of rows of image data, which arereferred to as “scanlines,” as the intermediate transfer member 212rotates the blanket 100 in the direction 216 past the optical sensor294A. In at least one embodiment, each optical detector in the opticalsensor 294A may include three sensing elements that are sensitive towavelengths of light corresponding to red, green, and blue (RGB)reflected light colors. In another embodiment, the optical sensor 294Amay include illumination sources that shine red, green, and blue light.In yet another embodiment, the sensor 294A may have an illuminationsource that shines white light onto the surface of blanket 100, andwhite light detectors are used.

The optical sensor 294A may shine complementary colors of light onto theimage receiving surface to enable detection of different ink colorsusing the photodetectors. The image data generated by the optical sensor294A may be analyzed by the controller 280 or other processor in theprinter 200 to identify the thickness of the polyurethane coating on theblanket 100. The thickness and coverage may be identified from eitherspecular or diffuse light reflection from the blanket 100 and/or thecoating. Other optical sensors 294B, 294C, and 294D may be similarlyconfigured and located in different locations around the blanket 100 toidentify and evaluate other parameters in the printing process, such asmissing or inoperative inkjets and ink image formation prior to imagedrying (294B), ink image treatment for image transfer (294C), and theefficiency of the ink image transfer (294D). Alternatively, someembodiments may include an optical sensor to generate additional datathat may be used for evaluation of the image quality on the media(294E).

The printer 200 may include an airflow management system 201, whichgenerates and controls a flow of air through the print zone. The airflowmanagement system 201 may include a printhead air supply 202 and aprinthead air return 203. The printhead air supply 202 and return 203may be operatively connected to the controller 280 or some otherprocessor in the printer 200 to enable the controller to manage the airflowing through the print zone. This regulation of the air flow may bethrough the print zone as a whole or about one or more printhead arrays.The regulation of the air flow may help to prevent evaporated solventsand water in the ink from condensing on the printhead and as well asattenuating heat in the print zone to reduce the likelihood that inkdries in the inkjets, which may clog the inkjets. The airflow managementsystem 201 may also include one or more sensors to detect humidity andtemperature in the print zone to enable more precise control of thetemperature, flow, and humidity of the air supply 202 and return 203 toensure optimum conditions within the print zone.

The printer 200 may also include an aqueous ink supply and deliverysubsystem 220 that has at least one source 222 of one color of aqueousink. Since the printer 200 is a multicolor image producing machine, theink delivery system 220 includes, for example, four (4) sources 222,224, 226, 228, representing four (4) different colors CYMK (cyan,yellow, magenta, black) of aqueous inks.

The printhead system 230 may include a printhead support 232, whichprovides support for a plurality of printhead modules, also known asprint box units, 234A-234D. Each printhead module 234A-234D effectivelyextends across the width of the blanket 100 and ejects ink drops ontothe blanket 100. A printhead module 234A-234D may include a singleprinthead or a plurality of printheads configured in a staggeredarrangement. Each printhead module 234A-234D may be operativelyconnected to a frame (not shown) and aligned to eject the ink drops toform an ink image on the coating on the blanket 100. The printheadmodules 234A-234D may include associated electronics, ink reservoirs,and ink conduits to supply ink to the one or more printheads. One ormore conduits (not shown) may operatively connect the sources 222, 224,226, and 228 to the printhead modules 234A-234D to provide a supply ofink to the one or more printheads in the modules 234A-234D. As isgenerally familiar, each of the one or more printheads in a printheadmodule 234A-234D may eject a single color of ink. In other embodiments,the printheads may be configured to eject two or more colors of ink. Forexample, printheads in modules 234A and 234B may eject cyan and magentaink, while printheads in modules 234C and 234D may eject yellow andblack ink. The printheads in the illustrated modules 234A-234D arearranged in two arrays that are offset, or staggered, with respect toone another to increase the resolution of each color separation printedby a module. Such an arrangement enables printing at twice theresolution of a printing system only having a single array of printheadsthat eject only one color of ink. Although the printer 200 includes fourprinthead modules 234A-234D, each of which has two arrays of printheads,alternative configurations include a different number of printheadmodules or arrays within a module.

After the printed image on the blanket 100 exits the print zone, theimage passes under an image dryer 204. The image dryer 204 may include aheater, such as a radiant infrared heater, a radiant near infraredheater, and/or a forced hot air convection heater 205. The image dryer204 may also include a dryer 206, which is illustrated as a heated airsource, and air returns 207A and 207B. The infrared heater 205 may applyinfrared heat to the printed image on the surface of the blanket 100 toevaporate water or solvent in the ink. The heated air source 206 maydirect heated air over the ink to supplement the evaporation of thewater or solvent from the ink. In at least one embodiment, the dryer 206may be a heated air source with the same design as the dryer 296. Whilethe dryer 206 may be positioned along the process direction to dry thehydrophilic composition, the dryer 206 may also be positioned along theprocess direction after the printhead modules 234A-234D to at leastpartially dry the aqueous ink on the blanket 100. The air may then becollected and evacuated by air returns 207A and 207B to reduce theinterference of the air flow with other components in the printing area.

The printer 200 may further include a print medium supply and handlingsystem 240 that stores, for example, one or more stacks of paper printmediums of various sizes. The print medium supply and handling system240, for example, includes sheet or substrate supply sources 242, 244,246, and 248. The supply source 248 may be a high capacity paper supplyor feeder for storing and supplying image receiving substrates in theform of cut print mediums 249. The print medium supply and handlingsystem 240 may also include a substrate handling and transport system250 that has a media pre-conditioner assembly 252 and a mediapost-conditioner assembly 254. The printer 200 may also include a fusingdevice 260 to apply additional heat and pressure to the print mediumafter the print medium passes through the transfix nip 218. The printer200 may also include an original document feeder 270 that has a documentholding tray 272, document sheet feeding and retrieval devices 274, anda document exposure and scanning system 276.

Operation and control of the various subsystems, components, andfunctions of the printer 200 may be performed with the aid of thecontroller 280. The controller 80 may be operably connected to theintermediate transfer member 212, the printhead modules 234A-234D (andthus the printheads), the substrate supply and handling system 240, thesubstrate handling and transport system 250, and, in some embodiments,the one or more optical sensors 294A-294E. The controller 280 may be aself-contained, dedicated mini-computer having a central processor unit(“CPU”) 282 with electronic storage 284, and a display or user interface(“UI”) 286. The controller 280 may include a sensor input and controlcircuit 288 as well as a pixel placement and control circuit 289. Inaddition, the CPU 282 may read, capture, prepare, and manage the imagedata flow between image input sources, such as the scanning system 276,or an online or a work station connection 290, and the printhead modules234A-234D. As such, the controller 280 may be the main multi-taskingprocessor for operating and controlling all of the other machinesubsystems and functions.

Once an image or images have been formed on the blanket 100 and coatingunder control of the controller 280, the printer 200 may operatecomponents within the printer 200 to perform a process for transferringand fixing the image or images from the blanket 100 to media. Thecontroller 280 may operate actuators to drive one or more of the rollers264 in the media transport system 250 to move the print medium 249 inthe process direction P to a position adjacent the transfix roller 219and then through the transfix nip 218 between the transfix roller 219and the blanket 100. The transfix roller 219 may apply pressure againstthe back side of the print medium 249 in order to press the front sideof the print medium 249 against the blanket 100 and the intermediatetransfer member 212. Although the transfix roller 219 may also beheated, as shown, the transfix roller 219 is unheated in FIG. 1B. Thepre-heater assembly 252 for the print medium 249 may be in the mediapath leading to the transfix nip 218. The pre-conditioner assembly 252may condition the print medium 249 to a predetermined temperature thataids in the transferring of the image to the media, thus simplifying thedesign of the transfix roller 219. The pressure produced by the transfixroller 219 on the back side of the heated print medium 249 mayfacilitate the transfixing (transfer and fusing) of the image from theintermediate transfer member 212 onto the print medium 249. The rotationor rolling of both the intermediate transfer member 212 and transfixroller 219 not only transfixes the images onto the print medium 249, butalso assists in transporting the print medium 249 through the transfixnip 218. The intermediate transfer member 212 may continue to rotate toenable the printing process to be repeated.

After the intermediate transfer member moves through the transfix nip218, the image receiving surface passes a cleaning unit that removes,among other things, residual ink from the image receiving surface of theblanket 100. In the printer 200, the cleaning unit is embodied as acleaning blade 295 that engages the surface of the blanket 100. Theblade 295 is formed from a material that wipes the surface of theblanket 100 without causing damage to the blanket 100. For example, thecleaning blade 295 may be formed from a flexible polymer material in theprinter 200. In another embodiment, the cleaning unit may include aroller or other member that applies a mixture of water and detergent toremove residual materials from the surface of the blanket 100 after theintermediate transfer member moves through the transfix nip 218. Theterm “detergent” or cleaning agent refers to any surfactant, solvent, orother chemical compound that is suitable for removing any residual inkfrom the image receiving surface of the blanket 100.

The topcoat layer 140 of blanket 100 may be a cured composition thatincludes a product of a grafting reaction between a fluoroelastomer andat least one of an aminosilane component and an aminofunctionalizedfluorosilicone (EF) component. The fluoroelastomer, aminosilanecomponent and the aminofunctionalized fluorosilicone component can becommercially available fluoroelastomer, aminosilane andaminofunctionalized fluorosilicone. The aminosilane component may bepresent in an amount relative to the fluoroelastomer of about 2 pph toabout 10 pph. The aminofunctionalized fluorosilicone component may bepresent in an amount relative to the fluoroelastomer of about 2 pph toabout 10 pph.

A “fluoroelastomer” is a fluorocarbon-derivative, a synthetic rubber.The term fluoroelastomer is well understood in the art. Afluoroelastomer or fluoro rubber of the polymethylene type usesvinylidene fluoride as a comonomer and has substituent fluoro, alkyl,perfluoroalkyl, or perfuoroalkoxy groups on the polymer chain.Fluorelastomers are categorized under the ASTM D1418, and have the ISO1629 designation FKM. This class of elastomer is a family comprisingcopolymers that contains monomers exclusively selected from the groupconsisting of hexafluoropropylene (HFP), tetrafluoroethylene (TFE),vinylidene fluoride (VDF), perfluoromethyl vinyl ether (PMVE), andethylene (ET). The term copolymer here refers to polymers made from twoor more monomers. Fluoroelastomers may contain two or three of thesemonomers, and have a fluorine content of from about 60 wt % to about 70wt %. Fluoroelastomers generally have superior chemical resistance andgood physical properties. Exemplary fluoroelastomers are available underthe TECNOFLON brand P959 from Solvay America, Inc. (Houston, Tex.) or asa VDF-TFE-HFP terpolymer under the DAI-EL brand G621 from DaikinIndustries (Houston, Tex.).

The aminosilane in the composition described above can be anyaminosilane-containing compound that can be reacted with thefluoroelastomer. For example, an exemplary aminosilane is anoxyaminosilane. The term “oxyaminosilane” refers to a compound that hasat least one silicon atom covalently bonded to an oxygen atom and thathas at least one amino group (—NH₂). The oxygen atom may be part of ahydrolyzable group, such as an alkoxy or hydroxyl group. The amino groupis not necessarily covalently bonded to the silicon atom, but may bejoined through a linking group. A general formula for an oxyaminosilaneis provided in Formula (1):Si(OR)_(p)R′_(q)(-L-NH₂)_(4-p-q)  (1),where R is hydrogen or alkyl, p is an integer from 1 to 3, R′ is analkyl, q is an integer from 0 to 2, L is a linking group, and 4-p-q mustbe at least 1. In an example, p is 2 or 3.

The term “alkyl” as used herein refers to a group composed entirely ofcarbon atoms and hydrogen atoms that is fully saturated. The alkyl groupmay include a chain that is linear, branched, or cyclic. For example,linear alkyl radicals generally have the formula —C_(n)H_(2n+1), where nis an integer.

The term “alkoxy” may refer to an alkyl group singular bonded to anoxygen atom.

The term “amino” refers to a group containing a nitrogen atom attachedby a single bond to hydrogen atoms, alkyl groups, aryl groups or acombination thereof. An “amine” is an organic compound that contains anamino group. Amines are derivatives of the inorganic compound ammonia.

Exemplary oxyaminosilanes include [3-(2-aminoethylamino)propyl]trimethoxysilane, as well as 3-aminopropyl trimethoxysilane. In3-aminopropyl trimethoxysilane, the propyl chain is the linking group.The aminosilane may be a commercially available aminosilane such asN-aminoethyl-2-aminopropyl trimethoxysilane from Sigma-Aldrich or UCT(sold as AO700). The amine functional group may be a primary, secondary,or tertiary amine. The nitrogen atom of an amino group can bond with thefluoroelastomer (i.e the oxygen atom will not bond with thefluoroelastomer).

Exemplary aminofunctionalized fluorosilicones (EF) can includeamino-functionalized alkoxy-terminated fluorosilicones such as EF0712128provided by Wacker Chemie AG (Munich, Germany) and can be represented bythe structure in formula (2):

A method for forming the topcoat layer 140 can include forming acomposition, such as a composition comprising the product of a graftingreaction between a fluoroelastomer and at least one of an aminosilanecrosslinker and an aminofunctionalized fluorosilicone crosslinker. asdescribed above, on a surface of the blanket. The method can includecuring the composition at a first curing temperature in the range of atemperature lower than about 218° C., for example a temperature of about23° C. for a first curing time, and/or curing the composition at asecond curing temperature that can be greater than the first curingtemperature, for example a second temperature in the range of lower thanabout 218° C., such as a second temperature of about 140° C.

The compositions comprising the product of a grafting reaction between afluoroelastomer and at least one of an aminosilane crosslinker and anamino-functionalized fluorosilicone crosslinker as described herein maybe formed by way of the reaction mechanisms shown in FIGS. 2A-2D andFIGS. 3A-3G.

The scheme illustrated by FIGS. 2A-2D shows reaction mechanism forforming a graft between an FKM fluoroelastomer, for example, DAI-ELG621, and an aminosilane agent, such as AO700 aminosilane agentN-aminoethyl-2-aminopropyl trimethoxysilane as the crosslinker graftingcomponent. FIG. 2A shows a first step of a dehydrofluorination in whicha fluoroelastomer, for example, DAI-EL G621, is caused to react withaminosilane, for example, AO700, resulting in a carbon-carbon doublebond in G621 (upon loss of a fluoride ion) and a partially reactedAO700. Step 2, shown in FIG. 2B, includes a step of adding an amine, forexample the terminal amine in AO700, across the double bond in theunsaturated G621 formed in step 1 to yield a product of a graftingreaction, that is, an aminosilane (AO700) grafted G621 composition.Then, in a third step shown in FIG. 2C, the AO700 grafted G621composition formed in step 2 undergoes a hydrolysis reaction to form ahydrolyzed AO700 grafted G621 composition. Finally, a fourthcondensation step shown in FIG. 2D shows the hydrolyzed AO700 graftedG621 undergoing a crosslinking reaction.

Meanwhile, the scheme illustrated by FIGS. 3A-3D shows reactionmechanism for forming a graft between an FKM fluoroelastomer, forexample, DAI-EL G621, and an amino-functionalized alkoxy terminatedfluorosilicone (EF) and aminosilane agent, such as AO700 aminosilaneagent N-aminoethyl-2-aminopropyl trimethoxysilane, as crosslinkers. Inparticular, FIG. 3A and FIG. 3B show a first step including paralleldehydrofluorination reactions in which G621 is caused to react with EFin a first reaction, and another G621 is caused to react with AO700 in asecond reaction resulting in a carbon-carbon double bond in each G621(i.e., unsaturated G621) (upon loss of a fluoride ion), and partiallyreacted EF and partially reacted AO700. Step 2 shown in FIGS. 3C-3Dincludes adding an amine, for example the terminal amine in EF, acrossthe double bond in the unsaturated G621 formed in step 1 to yield aproduct of a grafting reaction, that is, an EF grafted G621 composition(FIG. 3C), and a parallel step of adding an amine, for example theterminal amine in AO700, across the double bond in the unsaturated G621formed in step 1 to yield a product of a grafting reaction, that is, anaminosilane (AO700) grafted G621 composition (FIG. 3D). Then, in a thirdstep shown in FIGS. 3E-3F, the EF grafted G621 composition formed instep 2 undergoes a hydrolysis reaction to form a hydrolyzed EF graftedG621 composition (FIG. 3E), and in parallel, AO-700 undergoes ahydrolysis reaction to form a hydrolyzed AO-700 (FIG. 3F). Finally, afourth step illustrated in FIG. 3G shows condensation of hydrolyzedAO700 formed in step 3 onto the EF grafted G621 formed in step 2.

FIG. 4A shows a process 300 for forming AO700-grafted polymer from G621,in accordance with the synthesis mechanism shown in FIGS. 2A-2D. Inparticular, FIG. 4A shows a process 300 for manufacturing a graftedfluoroelastomer including preparing an 18.5% solution of G621 in methylisobutyl ketone (MIBK) (Part A) at 301, and preparing a solution ofAO700 and MIBK (Part B) at 303. Part A may consist of a very low amountof surfactant that provides good compatibility between G621 and therelease layer/oil applied on, for example, a fuser, while preventing pinholes/fish eye-type image quality defects. Part B can be prepared with aratio of AO700:MIBK of about 1:4 mol/mol. Each of Part A and Part B areindependently outgassed at 23° C. overnight and allowed to roll in orderto reduce any air bubble formation. Part B is then added dropwise intoPart A to form a solution comprising Part A and Part B.

FIG. 4A shows that at 305 the solution comprising Part A and Part B ismixed for 5 minutes at 23° C. At 307, the mixture is formed on asubstrate, for example, poured on the substrate, outgases (solventevaporation) and cures at 23° C. overnight. At 309, the solidifiedmaterial film is cured overnight at 140° C. The resulting composition isa crosslinked FKM graft, such as a crosslinked FKM graft topcoat layer.

By way of example, a solution in accordance with Part A and a solutionin accordance with Part B in FIG. 4A were prepared, rolled overnight at23° C. for about 16 to about 18 hours. Part B was added into Part Adropwise. Once the addition of Part B to Part A was done, the resultingsolution was poured into molds (6×6 inch) and kept at room temperatureovernight and then transferred to the oven which was kept at 140° C. for24 hours. The same solution was also flow coated on a Trelleborgsubstrate for evaluation as a blanket material in an aqueous transfixprint process.

FIG. 4B shows a process 350 for forming AO700-grafted polymer from G621,in accordance with the synthesis mechanism shown in FIGS. 3A-3D. Inparticular, FIG. 4B shows a process 350 for manufacturing a graftedfluoroelastomer including preparing a 18.5% solution of G621 in methylisobutyl ketone (MIBK) (Part A) at 351, and a solution of EF & AO700 inMIBK (Part B) at 353. Part A may consist of a very low amount ofsurfactant that provides good compatibility between G621 and the releaselayer/oil applied on, for example, a fuser, while preventing pinholes/fish eye-type image quality defects. Part B can be prepared with aratio of aminosilane to solvent, for example a ratio for AO700:MIBK, ofabout 1:4 mol/mol. Part B can be prepared with a ratio for aminosilanecomponent to aminofunctionalized fluorosilicone component, for example aratio for AO700:EF, in the range of about 0.5:1 mol/mol to about 3:1mol/mol, or about 1:1 mol/mol to about 2:1 mol/mol. Each of Part A andPart B are independently outgassed at 23° C. overnight and allowed toroll in order to reduce any air bubble formation. Part B is then addeddropwise into Part A to form a solution comprising Part A and Part B.

FIG. 4B shows that at 355 the solution comprising Part A and Part B ismixed for 5 minutes at 23° C. At 357, the mixture is formed on asubstrate, for example, poured on the substrate, outgases (solventevaporation) and cures at 23° C. overnight. At 359, the solidifiedmaterial film is cured overnight at 140° C. The resulting composition isa crosslinked FKM graft, such as a crosslinked FKM graft topcoat layer.

By way of example, a solution in accordance with Part A and a solutionin accordance with Part B in FIG. 4B were prepared, rolled overnight at23° C. for about 16 to about 18 hours. Part B was added into Part Adropwise. Once the addition of Part B to Part A was done, the resultingsolution was poured into molds (6×6 inch) and kept at room temperatureovernight and then transferred to the oven which was kept at 140° C. for24 hours. The same solution was also flow coated on a Trelleborgsubstrate for evaluation as a blanket material in an aqueous transfixprint process.

Fluoroelastomer compositions in accordance with embodiments and methodsof manufacturing are useful for other applications, including printingapplications other than the indirect aqueous transfix printing systemsdescribed above. For example, such fluoroelastomer compositions can beused as surface top-coat materials for the reimageable surface of animaging member in a variable data lithography system such as thatdisclosed in U.S. patent application Ser. No. 13/095,714 (“714Application”), titled “Variable Data Lithography System,” filed on Apr.27, 2011 by Stowe et al., the disclosure of which is hereby incorporatedby reference herein in its entirety.

The resulting grafted polymers were compared with related artcompositions. In particular, the mechanical properties of G621-AO700-EFand G621-AO700 were evaluated for comparison. The results are shown inTable 1.

TABLE 1 Stress at Strain at Initial Gelation Curing Break BreakToughness Modulus time Extractables Temperature Film ID (psi) (%)(in.-lbs./in.³) (psi) (hr) (%) (° C.) #1- 1074 237 1308  854 3.5 3.0 140G621(18.5%)/2 pph  (961-1207) (215-256) (1192-1533) (806-914) EF + 8pphAO700/no filler #3 - 1163 231 1393 1091 2.5 3.2 140 G621(18.5%)/10pph (1009-1263) (225-239) (1208-1496)  (998-1169) AO700/no filler #8- 570  56  172 1948 3.5 4.9 218 G621(18.5%)/8 pph (513-641) (54-60)(155-197) (1917-1985) AO700 + 2 pph EF/no filler #9- 1253  84  498 17512.5 5.2 218 G621(18.5%)/10 pph (1119-1406) (74-95) (406-610) (1651-1832)AO700/no filler G621(18.5%)/10 pph — — — — 24 10.8 140 EF/no fillerproduction fuser   1093.5 165   764.5   1597.5 N/A N/A 218 roll material

Table 1 shows that the mechanical properties of stress, strain andtoughness are comparable to conventional fuser roll material, which isindicative of a long life time. Also shown is that the mechanicalproperties degrade upon high temperature curing. Accordingly, AO700grafting is suitable for curing at lower temperature. Additionally, thegeleation time results show that the gelation time (i.e., the time for aviscosity change from 200 to 400 cp) is elongated from about 2.5 hoursto about 3.5 hours. Accordingly, because filtration, degassing and otherprocesses require more time during flow coating, the elongated gelationtime indicates wide latitude for flow coating the compositions describedherein. It is also noted that the results for extractables provides anindication of curing and mechanical properties. As shown in Table 1, thelower extractable values correspond to better mechanical properties. Itis noted that G621 with 100% EF resulted in poor values for extractablesand bad film appearance, and thus there was no need to test themechanical properties as reflected in Table 1. Last, it is noted thatcuring temperature results show that the curing temperature is decreasedfrom 218° C. in some instances to a value below 218° C., such as 140° C.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the disclosure are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Moreover, all ranges disclosed hereinare to be understood to encompass any and all sub-ranges subsumedtherein.

While the present teachings have been illustrated with respect to one ormore implementations, alterations and/or modifications can be made tothe illustrated examples without departing from the spirit and scope ofthe appended claims. In addition, while a particular feature of thepresent teachings may have been disclosed with respect to only one ofseveral implementations, such feature may be combined with one or moreother features of the other implementations as may be desired andadvantageous for any given or particular function. Furthermore, to theextent that the terms “including,” “includes,” “having,” “has,” “with,”or variants thereof are used in either the detailed description and theclaims, such terms are intended to be inclusive in a manner similar tothe term “comprising.” Further, in the discussion and claims herein, theterm “about” indicates that the value listed may be somewhat altered, aslong as the alteration does not result in nonconformance of the processor structure to the illustrated embodiment. Finally, “exemplary”indicates the description is used as an example, rather than implyingthat it is an ideal.

It will be appreciated that variants of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be combined intomany other different systems or applications. Various presentlyunforeseen or unanticipated alternatives, modifications, variations, orimprovements therein may be subsequently made by those skilled in theart which are also intended to be encompasses by the following claims.

What is claimed is:
 1. A polymer coating composition for a surfacelayer, comprising: a product of a grafting reaction between afluoroelastomer and at least one of an aminosilane component and anaminofunctionalized fluorosilicone component, wherein the aminosilanecomponent is present in an amount relative to an amount of thefluoroelastomer of about 2 pph to about 10 pph, and wherein theaminofunctionalized fluorosilicone component is present in an amountrelative to an amount of the fluoroelastomer of about 2 pph to about 10pph.
 2. The composition of claim 1, wherein the reaction product iscrosslinked.
 3. The composition of claim 1, wherein the aminosilanecomponent comprises an oxyaminosilane.
 4. The composition of claim 3,wherein the oxyaminosilane is represented by formula (1):Si(OR)_(p)R′_(q)(-L-NH₂)_(4-p-q)  (1), where R is hydrogen or alkyl, pis an integer from 1 to 3, R′ is an alkyl, q is an integer from 0 to 2,L is a linking group, and 4-p-q is at least
 1. 5. The composition ofclaim 1, wherein the aminofunctionalized fluorosilicone componentcomprises an am inofunctionalized alkoxy-terminated fluorosilicone. 6.The composition of claim 5, wherein the aminofunctionalizedalkoxy-terminated fluorosilicone is represented by formula (2):


7. A printing system comprising: an imaging member comprising asubstrate and a surface layer disposed on the substrate, wherein thesurface layer comprises a cured product of a grafting reaction between afluoroelastomer and at least one of an aminosilane component and anaminofunctionalized fluorosilicone component, wherein the aminosilanecomponent is present in an amount relative to an amount of thefluoroelastomer of about 2 pph to about 10 pph, and wherein theaminofunctionalized fluorosilicone component is present in an amountrelative to an amount of the fluoroelastomer of about 2 pph to about 10pph.
 8. The printing system of claim 7, wherein a the surface layer is atopcoat of a fuser subsystem.
 9. The printing system of claim 7, whereinthe surface layer is a topcoat of blanket for an aqueous transfixprinting system.
 10. The printing system of claim 7, wherein the surfacelayer is a reimageable surface layer of a digital printing system.